Getter for radio tubes



May 3, 1938. G. KING GETTER Fon RADIO TUBES Filed oci. 7, 19s5` FMS--l Patented May 3, 1938 UNITED STATES PATENTl OFFICE 1 Claim.

This invention relates to a process of evacuating radio tubes and of getters employed therein. It is an object of this invention to nd a new and improved process and getter material, suitable for 5 use with evacuated vessels having a metallic envelope such as metal radio tubes.

In the manufacture of radio tubes with a glass envelope, it has been customary to place the getter material within the envelope and then to vaporize it by the use of high frequency currents. With this method of vaporization the mechanical support afforded the getter material has taken the form of a more or less closed cup having a large liat rim.

When, however, a metal envelope is used in the manufacture of radio tubes, the getter material is placed in intimate thermo contact with the metal wall of the tube so that it may be vaporized by heat applied to the exterior of the tube at that point.

In order that the vaporization may take place with this system without undue heating of the Wall of the tube and Without other manufacturing difficulties, it has been proposed 'to drop a pellet of getter into a little indentation in the interior wall of the tube and then weld over it a small piece of nickel or other metal or screen. This has involved considerable labor and inconvenience and it has increased the cost of tubes materially. Several steps are required to place the pellet in position, then to position the metallic ribbon or screen and weld it into place.

It is an object of this invention to provide a new and improved getter which will function satlsfactorlly with metallic tubes with a minimum of labor and a maximum of efficiency. It is a further object to provide a getter which is ready for immediate mounting into the tube without the necessity of pre-forming the tube in any manner.

In accordance with this invention the getter material is bonded in a suitable manner to a metallic support of a form andynature suitable for welding to the interior of the metallic envelope and then the whole is rmly attached to the envelope as by welding.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the device embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplilied in the following detailed disclosure, and the scope of the application of which will be indicated in the claim.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawing, in which: Y

In the drawing the Figure l is a plan view of a getter embodying this invention.

Figure 2 is a longitudinal section of the same on the line 2--2 of Figure l.

Figure 3 is a similar view showing the getter applied to the inner wall of the envelope before 10 ignition.

In carrying out this invention, the getter material Ill, is formed into a pellet within a recess II, in a nickel sheet I2, the nickel sheet having substantially the curvature of the inside wall of the envelope I3 in which the getter is to be used. In some instances, however, I may prefer to make it of less curvature so that the pellet itself is held firmly against the wall.

To' achieve this result I have found it practical 20 to employ a getter material in powdered' form which is placed on a metallic sheet I 2 which is then indented as at I I, at the same time that the getter material is compressed into a pellet I0 within the indentation. This results in the ior- 20 mation of the getter shown in Figures l and 2, and in its preferred form it will be noted that the getter material extends beyond the outer walls of the indentation II, so as to touch the wall of the tube.

The sheet I2 is bent to conform to the inner wall of the container I3 as shown in Figure 2 and in use it is placed against the inner wall as shown in Figure 3 and spot-welded to it as 35 shown at I4. At this step, by reason of the fact that the pellet of getter extends beyond the edges of the indentation, it is held rmly'against the walls of the envelope itself so that when heat is applied externally to the envelope it is immedi- 40 ately transmitted to the getter.

A getter made in accordance with this invention is practical and eiiicient in use and avoids considerable labor.

Since certain changes in carrying out the above 45 process and in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claim is intended to cover all of the generic and specic features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is: A getter for radio tubes and the like having an outer envelope of metal comprising a strip of metal having a general contour of a portion of the interior of said envelope and having imbedded therein upon the outer surface thereof a pellet of getter material whereby when said metal is attached to the inner face of a. radio tube envelopeI the getter material will be in Contact with the 5 envelope.

GEORGE L. KING. 

